Studies of the Deposition of Sub-Micron Particles on Turbine Blades

Abstract

The paper describes the continuation of work to evaluate the magnitude of diffusional deposition of small particles on turbine blades. Apparatus and techniques similar to those described in an earlier paper have been employed. Modifications were necessary to overcome the problem of electrostatic charging of the deposition surface affecting the deposition results. Test results for the distribution of deposited particles around the blade have been obtained for three mass median diameters of 0·13, 0·19 and 0·24 μm and the influence of the level of turbulence at inlet to the cascade assessed. A theoretical treatment is derived which satisfactorily predicts the experimental results for the case of low inlet turbulence level. The paper also gives details of the technique, using electron microscopy, of obtaining size distribution data for the minute particles.